S. A. GEARHART Testing the SM-3 Kinetic Warhead in the Guidance
System Evaluation Laboratory
Scott A. Gearhart
S
tandard Missile-3 (SM-3) is being developed as part of the Navy’s Aegis Lightweight
Exo-atmospheric Projectile Intercept Program, known as ALI, which is intended to demonstrate an Aegis ship engagement of a tactical ballistic missile test target in the exoatmosphere. As part of the Laboratory’s long-established role as SM Technical Direction
Agent, we are conducting ground testing of key SM-3 components (flight computers, guidance systems, navigation systems, communication links, etc.) in APL’s Guidance System
Evaluation Laboratory (GSEL). This article focuses on the GSEL testing of the kinetic
warhead, the infrared-guided fourth stage of SM-3 that is ejected in the terminal phase of
flight to acquire, track, and intercept the target.
INTRODUCTION
APL’s Guidance System Evaluation Laboratory
(GSEL) is a test facility dedicated to long-term support
of the Navy’s Standard Missile (SM) Program. Since
the 1960s, the GSEL has performed guidance system
testing for all SM variants. These tests have provided
missile flight test risk reduction, postflight test assessment, rapid investigation of design and performance
issues, and missile production screening. Because the
GSEL uses personnel, test methods, and test equipment
that are not tied to the contractor’s test program, the
facility provides a complementary test capability and a
second, independent assessment of design integrity and
missile flight readiness. GSEL test capabilities are continually evolved to meet the needs of each new type of
SM (see the article by Marcotte et al., this issue). SM-3
is the newest system being tested. This article focuses
specifically on GSEL testing of the SM-3’s infrared (IR)
guided kinetic warhead (KW).
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The SM-3 KW is unique in several respects compared with other IR guided missiles tested in the GSEL.
First, it is essentially a spacecraft whose IR seeker detects
and tracks objects against cold space as opposed to terrestrial backgrounds. Second, the IR seeker has no gimbals but instead is hard-mounted to the KW body in a
“strap-down” configuration. To search a region of interest, the entire KW body maneuvers to steer the IR
seeker line of sight, resulting in tighter coupling between
seeker and guidance functions. Third, the KW’s IR
seeker operates in a wavelength regime different from
other SM IR seekers, and also has a comparatively larger
optical aperture, better sensitivity, and higher optical
resolution. Finally, the KW carries no explosive warhead. Its destructive force relies on direct impact with
the target at high speed, placing greater demands on
guidance system responsiveness. Such a departure from
previous systems required the development of new test
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
TESTING THE SM-3 KW IN THE GSEL
methods and equipment. This article presents an overview of the GSEL’s KW test program, including pertinent background discussions.
ALI PROGRAM
The objective of the Aegis Lightweight Exo-atmospheric Projectile (LEAP) Intercept (ALI) Program is to
develop and demonstrate an enhancement to the Aegis
Combat System that provides the capability to engage
a nonseparating tactical ballistic missile test target in
the exo-atmosphere (i.e., above about 100 km altitude).
The ALI effort involves the development of new Aegis
computer programs as well as the development of the
SM-3 missile to perform the hit-to-kill target intercept.
It includes a series of control test vehicle flights that
began in mid-1999 to incrementally prove ALI system
functions, culminating in a series of full-up system tests
to begin in late 2001. A number of defense contractors
are participating in the ALI Program including Lockheed
Martin Government Electronics Systems, Raytheon Missile Systems, Boeing North America, and Thiokol.
Figure 1 depicts the ALI mission sequence, which
begins with the launch of the test target from the
range. The shipboard Aegis SPY-1 radar acquires the
target and establishes track, and the Weapons Control
System issues a missile engagement order. The Vertical
Launching System next provides electrical power to
SM-3 and transmits prelaunch engagement data. The
missile batteries are then activated, built-in tests are performed, and missile launch occurs. During the early phase
of flight, the SPY-1 radar transmits guidance commands
to the missile. Later, the missile derives its own guidance commands using uplinked SPY-1 target and position data. In the terminal phase of flight, the KW autonomously guides to the target using its IR seeker.
SM-3 is a four-stage missile. Stages 1 and 2 include
rocket boosters and the steering control system necessary
for achieving exo-atmospheric altitudes. Each motor is
separated from the upper stages after burnout. In addition to the third-stage rocket motor, Stage 3 contains
guidance, control, and navigation systems, the communication link to the Aegis ship, and the nosecone which
protects the fourth-stage KW during flyout. After Stage
3 rocket motor burnout and nosecone deployment, the
KW is ejected. It then acquires the target with its IR
seeker and guides to intercept using its guidance system
and Solid-rocket Divert and Attitude Control System
(SDACS) rocket motor. The combination of motors from
Stages 1 to 3 provides the kinetic energy needed for the
KW to destroy the target on impact. The KW’s SDACS
provides lateral thrust maneuverability. Figure 2 illustrates the components of the KW.
Exo-midcourse phase
Seeker
calibration
KW ejection
Third stage,
second burn
SM-3 launch
Nosecone
ejection
GPS hot start
(varies with
scenario)
Third stage,
first burn
Endo-midcourse phase
Terminal
phase
Acquire, track, divert
Schedule
Engage
Second stage
Target burnout
Detect
SM-3 readiness
checkout
(prior to mission)
Pacific Missile
Range Facility
Boost (acquire)
Figure 1. ALI mission sequence.
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
303
S. A. GEARHART SDACS
IR seeker
Ejector
assembly
Guidance
assembly
Lateral
divert
Figure 2. The SM-3 KW.
KW TEST CONSIDERATIONS
The elements of the GSEL KW test program and
requirements for new test capabilities were dictated by
the KW’s mission, functions, and operating environment. Some considerations that are unique to the KW
as compared to other IR guidance systems are discussed
in the following sections.
Coupled Seeker and Guidance Functions
Typically in testing IR guidance systems it is common
to delineate tests into groups partitioned by component or function (e.g., seeker functions, guidance functions, etc.). Structuring tests in this manner assumes
that certain functions can be treated as independent,
i.e., not coupled. Not having to simultaneously test certain seeker and guidance functions makes the test setup
for each functional group less complex and the test process more efficient. Once the tests are completed, a
comparatively smaller number of more complex systemlevel tests is conducted to assess any known or unknown
interactions among functional groups.
KW testing also partitions into convenient test
groups; however, the coupling between seeker and guidance unit functions is greater than in past experience,
and more frequent and extensive system-level tests are
required. Coupling among component functions is due
largely to the KW’s strap-down IR seeker design, which
requires the IR seeker line of sight to be steered by
controlling the KW’s body orientation. In other SM
IR seeker designs, the seeker mounts on an inertialstabilized platform intended to keep the line of sight
unperturbed by missile body motion. Although these
other applications need to assess subtle body motion
coupling effects onto the seeker platform, the seeker,
for many tests, can be assessed independently of the
304
guidance system. This simplification is less valid for the
KW’s IR seeker.
The tighter coupling of KW seeker and guidance unit
functions is apparent in the track function. To maintain track on a target image that moves continuously
with KW body motion, the guidance unit measures body
motion and feeds these data to the IR seeker, which
propagates the track gate position (the window of focalplane-array pixels within which the target must remain
to maintain valid track) from one frame to the next.
Thus, the appropriate stimuli must be provided to both
the IR seeker and the guidance unit to fully test the
track function.
Space Background
At the operational altitude of the KW, the IR seeker
views a cold space background having low radiance.
Consequently, IR radiant emissions and reflections from
its own internal components dominate the seeker’s
detected background level, which equates to an apparent background temperature of about 210 K (–63°C).
From a practical standpoint, this background temperature is well below laboratory ambient room temperature; hence, a method to simulate cold backgrounds is
required for some types of tests.
The most accurate method for simulating a cold
space background necessitates the use of a cryogenic
vacuum chamber, often with the seeker enclosed in the
chamber and inaccessible should a system failure occur.
This approach requires expensive equipment, increases
the risk to high-value test assets, and entails extensive
periods for integration and checkout. Fortunately, only
a few types of tests require a cold background; the majority of KW tests can be performed in the ambient laboratory environment. Moreover, since high seeker radiometric accuracy and sensitivity are not needed in the
ALI mission, simpler and less risky methods can be used
to simulate a cold background (albeit not as cold as
could be achieved in a space chamber). The apparatus
developed in the GSEL to superimpose a test target
onto a cold background is described later in this article.
In the future, as the ALI System evolves to a tactical
system, some level of cryogenic vacuum chamber testing
may be required.
Hit-to-Kill Target Intercept
In the testing of earlier SM variants, the shape of
the laboratory IR test target and its radiance distribution
were of minimal importance. Indeed, simple expanding
apertures back-illuminated by a hot source were adequate to emulate target image growth as range decreased,
because target structure in a real engagement would not
be discernible until just before intercept. Even if IR
seeker tracking errors occurred owing to hot parts on
the target structure, the guidance system would already
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
TESTING THE SM-3 KW IN THE GSEL
be commanding maximum acceleration and hence could
not respond to these track anomalies. This is not necessarily true for the KW. Physically striking a point on the
target body requires a highly responsive guidance system
that is sensitive to target image shape and radiance distribution just before impact. This consideration prompts
the need for more sophisticated and expensive IR target
projection devices for a subset of tests.
GSEL APROACH FOR KW TESTING
A KW unit under test in the GSEL is shown in
Fig. 3 mounted in a fixture on an optical table. Although
a real SDACS is not tested for safety reasons, its effects
are modeled in the KW hardware-in-the-loop (HIL)
simulation described later.
As Fig. 3 shows, the KW requires an ensemble of
support equipment for activation and initialization as
well as video and telemetry data collection. The KW
control console developed by Boeing emulates power,
ordnance, and communications interfaces between
the KW and Stage 3 prior to KW ejection. This console provides the capability to execute user-specified
simulated mission sequences from SM-3 launch to target
intercept, and to vary the contents of KW state initialization messages. It also emulates KW battery power
and provides other support functions such as utilities for
downloading special test software and new versions of
flight computer programs. The KW telemetry console,
also developed by Boeing, allows monitoring, collection, and analysis of KW telemetry. Similarly, the DAS
2000 developed by Raytheon provides the capability to
collect and analyze video from the KW IR sensor. Without this ensemble of support assets, testing of the KW
would be impossible or at best greatly limited.
KW telemetry
control
KW control console
(Stage 3 emulator)
Telemetry
DAS 2000
Power
Initialization data
Ordnance activation
Flight computer
programs
IR seeker
video
KW
SDACS load
emulator
Compressed
nitrogen
Vortex
cooler
Vacuum
pump
Figure 3. The KW unit-under-test configuration in the GSEL,
showing test support equipment.
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
Consistent with established practice in the GSEL,
evaluation of the KW progresses from tests of selected
low-level functions to more complicated system-level
tests. In this context, low-level functions are basic operations that are either prerequisite to or fundamentally
inherent to the execution of high-level mission functions. Once the selected set of low-level functions is
confirmed, tests of mission functions are conducted by
iteratively traversing through increasingly larger portions of the ALI mission timeline in simulated flight
sequences, culminating in full-up HIL simulations from
missile launch to target intercept. Table 1 provides
examples of IR seeker and guidance unit low-level functions tested during initial KW checkout and lists the
associated ALI mission function sequence.
This incremental approach, progressing from simple
to more complex tests, has been shown from our experience to build fundamental knowledge and intuition
that is essential to recognizing and isolating anomalies
observed in the later more complex test configurations.
Results from early tests are also used to develop and validate models used in digital simulations. Digital simulation results provide a key primer to interpreting the
results of more complex system-level tests like HIL
simulation.
Equipment to test the KW varies in complexity from
simple IR collimators and blackbody sources, to point
target generators, to complex IR scene projectors and
HIL simulations. The GSEL test equipment is either
developed in house or built to GSEL-specific requirements by outside vendors. Test equipment typically is
designed to provide modularity and flexibility, assuming
that it will later need to be reconfigured or augmented
to address new test needs. In general, it is not possible
to foresee all equipment needs at the start of a test program; a test requirement may be discovered only after
test experience with the KW is attained.
As a rule, the criterion for choosing a particular test
equipment configuration is to select the one that provides the highest-fidelity representation of the flight
environment attributes important to the specific component or function being tested. For example, a simple
collimator with a moving pinhole target more accur-
ately represents a distant moving IR target for detailed
acquisition and track studies than a complex resistor-array IR scene projector that might exhibit spatial
anomalies associated with its discrete pixels. Conversely,
the latter device is more appropriate for testing IR
seeker processor loading while tracking multiple objects
or testing endgame track performance when the seeker
views details of the target shape. Experience suggests
that building a single piece of test apparatus that suits
all test needs is impractical; thus, a collection of different test assets is required.
The five primary KW test configurations in the GSEL
(Table 1) are as follows:
305
S. A. GEARHART Table 1. KW testing in the GSEL.
Low-level functions tested
during KW checkout
Seeker
Imaging Sensing Noise Guidance unit
Initialization
State propagation
Attitude processing
Inertial stabilization
1
Flood
ilumination
ALI mission-level function sequence
Pre-eject
1. Activate
2. Cool down focal plane array
3. Receive/process time sync
4. Transfer alignment
5. Initialize
6. Calibrate in flight
7. Activate battery
Post-eject
8. Eject 9. Ignite SDACS sustain
10. Navigate
11. Control
12. Search
13. Acquire target
14. Select target
15. Track target
16. Ignite SDACS divert
17. Guide to target
18. Select aimpoint
19. Track extended track
20. Hit target
21. Assess mission success
aTest
GSEL test configurationsa
2
3
4
Point
Rate
KW/Stage 3
target
table
connect
X
X
X
X
X
X
X
X
X
X
X
Limited testing
X
X
X
X
X
Emulated: real battery not tested
X
X
Ejector not tested
Emulated: real SDACS not tested
X
X
X
X
X
X
X
Emulated: real SDACS not tested
5
HILb
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
configurations are detailed in the text.
with and without the KW connected to Stage 3.
bPerformed
1. Flood illumination
2. Point target on ambient or cold background
3. KW on rate table viewing point target
4. KW connected to Stage 3 avionics
5. HIL
Configuration 1 uses a cryogenic, temperature-controlled, extended-area blackbody source that is placed
directly in front of the KW to characterize sensor performance. Configuration 2 is an APL-developed point
target generator incorporating a novel approach that
superimposes the target on a cold background, well
below ambient room temperature, without employing
a space vacuum chamber or cooled optics. The KW
306
typically mounts on a mechanized platform that nu-
tates the KW body analogous to flight. In Configuration 3, the KW is attached to a precision single-axis
rate table for characterizing body motion coupling
into the KW’s reported target positions and rates.
During these tests, the KW tracks a point target generated with the apparatus of Configuration 2. Configuration 4 links the KW to the Stage 3 avionics (being
tested elsewhere in the GSEL) to confirm this critical interface. (During most other KW tests in the
GSEL, the KW control console emulates the Stage
3 interface.) Finally, Configuration 5 is a HIL simulation that includes a resistor-array IR scene projector capable of projecting complex and dynamic IR
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
TESTING THE SM-3 KW IN THE GSEL
scenes. The unique test apparatus used in these test
configurations is discussed in the next section.
Simple equipment configurations are used in the
early tests partly for expedience, since the intent is to
provide a quick assessment of basic operations before
proceeding with more complicated tests. Also, in some
cases, the simple test configuration provides the best
fidelity for the low-level function tested. In addition,
some functions are assessed in more than one test configuration. For example, mission functions in Table
1 such as “acquire target,” “select target,” and “track
target” are tested both in Configuration 2, which provides a higher-fidelity point target representation, and
in Configuration 5, which provides a test of “end-toend” functional continuity.
UNIQUE TEST CAPABILITIES
As driven by considerations discussed previously,
testing of the KW required upgrades to the GSEL’s test
capability. This section describes some specifics on the
more unique and innovative upgrades.
Cold Background Point Target Generator
Figure 4 is a diagram of the cold background point
target generator devised by GSEL engineers. The
KW seeker views into an enclosure whose interior is
reflective. As shown in the figure, a highly reflective
beamsplitter (a partially reflecting mirror) mounted in
the enclosure reflects cold blackbody radiation from a
cryogenically cooled plate into the KW seeker aperture.
Since the enclosure is reflective, wall blackbody emissions into the KW are low. Furthermore, ambient room
temperature radiation that would normally enter from
outside the enclosure is reflected away by the beamsplitter which acts as a radiation seal. In this way, the KW
effectively views a background temperature well below
ambient room temperature without employing a space
vacuum chamber or cooled optics.
Point target radiation generated outside the enclosure enters through the beamsplitter, which, though
mostly reflective, does transmit about 5%. (The intensity of the test target is increased to compensate for the
low beamsplitter transmission.) The test target assembly comprises a smooth gold-coated plate that contains
a small hole back-illuminated by the target blackbody
source. As Fig. 4 shows, a second large-area cryogenic
source reflects from the gold face into the KW seeker’s
field of view to further emulate a cold background surrounding the target. The target assembly also includes
an APL-designed collimating lens, a motorized target
intensity attenuator, and a motion stage to provide one
axis of target motion. To prevent frosting and misting
of the cold air near the cryogenic source, the entire
apparatus is enclosed in a Plexiglas box purged with
nitrogen.
Measurements show that a moving point target can
be superimposed on a background-equivalent blackbody
temperature of about 182 K (–91°C), compared to ambient room temperature, which is about 293 K (20°C).
Although better performance would be achievable using
an optical suite in a cryogenically cooled vacuum chamber, the approach described here is adequate for many
types of tests at relatively low cost and risk to the KW.
In addition, the apparatus requires little setup and can
be used on a day-to-day basis.
IR Scene Projection System
The IR scene projection system used in the GSEL
has two components: the Scene Generation Computing
System (SGCS) developed by Matra/British Aerospace
and the Thermal Picture Synthesizer (TPS), a resistorarray IR scene projector developed by British Aerospace
Sowerby Research Center. Capabilities for dynamic
IR scene projection are possessed by only a few other
organizations worldwide.
The SGCS renders multiple IR
objects on a background and proTarget intensity
Motion
Nitrogen-purged
duces a corresponding digital image
attenuator
stage
box
that provides the input to the TPS.
Object models are files containing
Cryogenic
vertex coordinates that define the
sources
Gold target
Enclosure
object surface facets and the temHighly reflective
plate
with reflective
beamsplitter
perature of those vertices. For a
interior
Target
commanded viewing geometry, the
radiation
SGCS transforms the view of object
facets into the observer’s (i.e., the
KW
IR seeker’s) field of view and computes the apparent temperatures of
each facet, including the effects
Cold background
Collimating
Ambient radiation
of blackbody emission, solar and
radiation
lens
rejected
Earth reflections, and atmospheric
Figure 4. Cold background point target generator concept.
attenuation (if needed). The scene
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
307
S. A. GEARHART is next converted to a 10-bit graylevel digital image and output to
the TPS in a video line-by-line
format starting at the center of
the display and progressing outward. The SGCS is synchronized
to operate at the frame rate of
the IR seeker under test. It can
render up to 350 facets in the
scene at up to a 120-Hz frame
rate. The SGCS total data latency,
from scene geometry command
input to digital image output, is
about 17 ms.
Thermal
The TPS includes drive elecpicture
synthesizer
tronics, water cooling and argon gas
(IR display)
handling systems, and the display
unit. The display has 256  256
pixels, which are vacuum-sealed
behind an IR transmissive window.
The architecture of each pixel is
a serpentine heating coil (akin to
a heating element on an electric
range stove) that is suspended for
thermal isolation above the lowerlayer address circuitry by small
posts. The TPS is calibrated to radiate up to an equivalent blackbody
temperature of 473 K (200°C), at
frame rates of up to 120 Hz. Its addressing architecture
uses 256 digital-to-analog converters to update each
video line. The entire display can be updated in 6 ms.
KW HIL Simulation
The KW HIL simulation (Fig. 5) is an ensemble
of computers and emulators intended to provide a virtual flight environment to the KW. Core to the HIL
simulation is a flight dynamics simulator that processes
body motion commands from the KW guidance system,
computes the SDACS propulsion and body motion
response, and relays this information to emulators that
provide stimuli back to the KW, thereby closing control and guidance loops. One emulator in the HIL simulation is the inertial measurement unit (IMU) that
provides body motion measurements to the KW analogous to its own IMU (which is disconnected from the
guidance unit during HIL testing). The second emulator is the IR scene projection system that provides
dynamic IR scenes to the KW’s IR seeker using the
SGCS and TPS discussed previously. The motion of
objects projected into the seeker’s field of view includes
the combined effects of target and KW body motion.
The KW HIL simulation is operated in either of two
modes: open loop using scripted IMU emulator data
and IR scene geometry inputs, or closed loop as already
described. The open loop mode is useful for testing the
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KW HIL simulation
control computer
SGCS
Scene
geometry
and frame
sync
IMU emulator
SDACS
ignition signal
Target dynamics
Emulated IMU
Sync and I/O
SDACS propulsion
IR
scene loop
IMU loop
Flight dynamics
simulator
Sync
signals
Control and
guidance
commands
Video and telemetry
Optics
KW
KW control console
(Stage 3 emulator)
Figure 5. KW HIL simulation.
IR seeker without the complexities of a closed loop
test. In particular, parametric studies can be performed
to assess the IR seeker’s response to varying KW body
motion perturbations. The closed loop mode, although
more complex, captures seeker and guidance unit interactions as well as real-time sensitivity to off-nominal
propulsion conditions (e.g., stuck or leaking SDACS
thruster valves). Challenges to developing the KW HIL simulation
included tight synchronization of emulated data streams
and the control and compensation of data latency.
Here, data latency is the delay between the time that
the KW guidance system issues a command and when
the HIL emulators provide a response back to the KW.
Because of the computations required, IR scene projection latency is the largest contributor. The effects of
scene latency are compounded by the KW’s strap-down
IR seeker configuration, since the target image moves
with KW body motion. If uncompensated latency is
large enough or the image motion perturbations severe,
the target could be placed in the scene outside the seeker’s time-propagated track gate, causing loss of target
track. Characterizing and compensating for data latency
sources, and achieving precise synchronization of the
HIL simulation elements, took many months of meticulous integration testing before successful closed loop
simulation runs were demonstrated.
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
TESTING THE SM-3 KW IN THE GSEL
STATUS OF THE TEST PROGRAM
APL received the KW and its support equipment from
Raytheon and Boeing in late July 1999. After a period
for integration and checkout, as well as training for APL
personnel in KW and support equipment operations,
testing began in the fall of 1999 with detailed characterization of the IR seeker low-level functions. Measurements of seeker imaging attributes like optical efficiency,
distortion, and magnification were completed, as were
measurements of sensor function parameters including
responsivity, spectral response, temporal noise, and fixed
pattern noise. Some of these fundamental measurements
were repeated in April 2000 to quantify changes in seeker
performance after a 5-month interval. Since the GSEL
is the only facility testing a single KW over an extended
period, measurements of time stability of the IR seeker’s
original factory calibration and any degradation in the IR
focal plane array over time are of key importance.
After confirmation of the low-level seeker and guidance unit functions listed in Table 1, KW mission function testing began in preparation for two flight test
rounds (1 and 1A). Since these flight exercises were
aimed at testing SM-3 Stage 1 through 3 functions,
operational requirements for the KW were minimal.
Nevertheless, both flight rounds included a functional
KW with an inert SDACS, and there was potential to
collect KW telemetry data useful for risk reduction on
future flight tests. Furthermore, FTR-1A included a test
target identical to the one to be used for the later ALI
intercept flights, and collection of KW seeker data was
of great interest. Accordingly, open loop KW HIL tests
were conducted to verify KW mission functions shown
in Table 1 from activation through track target. In
addition, GSEL testing was performed to assess a proposed modification to the FTR-1A mission that would
delay ejection of the KW to provide a longer target viewing opportunity. Based partly on GSEL test data, the
mission modification was adopted and was ultimately
successful.
Closed loop KW HIL test capability was demonstrated in November 2000, and tests are now being
performed from KW activation through target intercept using the approach presented earlier of incrementally progressing through larger portions of the mission
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)
timeline. Timeline testing is being performed for a
number of scenarios that include off-nominal conditions like multiple objects in the seeker field of view
and potential missed-switching of the SDACS valves.
As part of these tests, a connection has also been made
between the KW and the SM-3 Stage 3 avionics suite
tested elsewhere in the GSEL to verify the KW to Stage
3 interface.
KW computer programs that will be used in the next
SM-3 flight missile test, FM-2, were recently delivered
to the GSEL. The FM-2 missile will include a fully
functional KW, including a live SDACS rocket motor.
GSEL risk reduction testing for FM-2 is under way.
CONCLUSION
KW testing in the GSEL will continue through the
ALI test flights, with a later shift to the collection of
test data pertinent to the development of more sophisticated SM-3 tactical variants. Planning is beginning now
to ascertain what GSEL enhancements are required for
the testing of these more advanced systems.
The Navy SM sponsor relies on GSEL engineers and
test activities to aid in missile development and flightreadiness decisions. The GSEL is a key element in fulfilling APL’s trusted agent role. It cannot be overemphasized that the GSEL’s credibility and value in this regard
hinge on the continued hands-on experience of GSEL
engineers working the practical problems involved in
developing and testing real systems.
ACKNOWLEDGMENTS: The author acknowledges the GSEL KW test and
equipment development teams for their work and dedication to this effort: Christina Chomel, Laurel Funk, James Garcia, Michael Mattix, Todd Neighoff, Robert
Patchan, Rick Tschiegg, Katy Vogel, and Duane Winters. In addition, the author
acknowledges Terry Hipp (no longer at APL) who led early KW HIL development efforts. Thanks also to KW test and development teams at Raytheon Missile Systems, Tucson, AZ, and at Boeing, Canoga Park, CA, led by Mike Leal
and Dan Tubbs, respectively, for their collective support. Special thanks to Hans
Acosta (Raytheon), Phil Pagliara (Raytheon), Matt Ryan (Boeing), and Terry
Sapp (Raytheon), who were our primary liaisons and made noteworthy efforts to
ensure that our needs were met. Our appreciation also to Bill Baurer, Pat Buckley,
Robin Lewis, and Brian Malone of Boeing who have been of great assistance in
maintaining, augmenting, and troubleshooting KW support equipment on site.
The author also acknowledges APL’s Bill Mehlman, who was key to getting the
KW test effort started during his tenure as SM-3 Program Manager, and current
APL Program Managers Tom Eubanks and Gary Sullins for their unwavering support and patience. Finally, our thanks to our NAVSEA PMS 422 sponsors CAPT
C. M. Bourne and Clay Crapps for the opportunity to perform stimulating and
relevant work.
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S. A. GEARHART THE AUTHOR
SCOTT A. GEARHART received a B.S. in engineering science from the Pennsylvania State University in 1982 and an M.S. in electrical engineering from the University of Maryland in 1987. He is a member of APL’s Principal Professional Staff
and a section supervisor in ADSD’s Electro-Optical Systems Group. Mr. Gearhart
joined APL in 1983 and has worked primarily on the development, test, and evaluation of optical and infrared guidance systems. He has led several efforts in APL’s
GSEL to develop infrared system test capabilities in support of the Navy’s Standard Missile Program. Most recently, Mr. Gearhart led APL’s effort in developing
capabilities for testing the Standard Missile-3 infrared-guided kinetic warhead. His
e-mail address is scott.gearhart@jhuapl.edu.
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JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 22, NUMBER 3 (2001)